CUPERTINO — Already considered a bane by local residents and labeled among the Bay Area’s top industrial polluters, Lehigh Permanente Quarry submitted an application this week that would substantially expand its mining operations by digging a second pit at the site, the first new pit since the quarry began mining in 1903.

Lehigh’s proposal calls for a new pit within a 60-acre area that would produce an estimated 60 million tons of limestone, aggregate and minerals. The company intends to plug up the original pit with on-site and imported materials by 2060 after it’s fully mined, according to a project description submitted to Santa Clara County planners.

“A local source of construction materials and cement reduces the environmental footprint of regional construction, and provides local jobs and tax revenues,” Erika Guerra, the company’s environmental and land management director, said in a written statement. “It’s all about producing and consuming locally, and the associated community and regional environmental benefits.”

The application is sure to stir more controversy among Cupertino residents in neighborhoods that have grown around the quarry and its cement plant over the past several decades, who have long complained about pollution, noise and dust generated by the operation.

County Supervisor Joe Simitian, whose district includes the quarry, said neighbors have been complaining about the quarry since his first year on the board in 1997.

“In a perfect world you wouldn’t have a major quarry and cement plant immediately adjacent to substantial suburban residential development, but that’s the situation we got,” Simitian said.

The Board of Supervisors gave the quarry vested rights in 2011, a recognition that Lehigh’s mining operations were legally established and can continue until the use ceases. The company says the new mining area falls within the geographic boundary of those vested rights.

County officials have been expecting the application for the past few years, Simitian said, noting that Lehigh has discussed a second pit for several years and filed an application in 2010 but later withdrew it.

In addition to a new mining area, the application spells out changes to how the quarried land will be restored over time.

Lehigh previously planned to use a 48-ton pile of limestone overburden, crushed materials which aren’t suitable for use in cement or construction, to backfill the current pit, but determined that moving rock around would re-expose surface and groundwater to contaminants, according to the project description.

Instead, the new application proposes using other non-limestone rock and imported construction soil from regional projects to backfill the current mining pit, which the company says will reduce the risk of water contamination.

Rhoda Fry, a Cupertino resident who has objected to the environmental impacts of the mining, said while dust and particulates are an unavoidable part of the operation, the company could do a much better job of reducing greenhouse gases and air pollution.

“The cement plant creates more pollution than it needs to — they have elected not to run it cleanly,” Fry said in an interview.

She said the new plan, which includes importing more materials to the quarry, “is a big deal that would create traffic and pollution.”

The company says surplus construction soil would have to be transported anyway.

“Without use at Permanente Quarry, much of the surplus construction soil generated in the region would need to be transported farther distances,” Guerra said.

Lehigh provides 80 percent of the cement used in Santa Clara County and more than half used in the entire Bay Area, according to the company.

It’s also one of the region’s major polluters, ranking eighth in 2017 for total emissions among top Bay Area industrial sites, according to data from the U.S. Environmental Protection Agency.

In 2013, the Sierra Club won a settlement that required Lehigh to install an interim wastewater treatment system. Two years later, the company agreed to pay $7.5 million to the EPA to settle charges it dumped millions of gallons of toxic wastewater into a nearby creek.

More recently, Cupertino residents complained about dust, noise and traffic after the company began hauling trucks of crushed rock on city streets to the adjacent Stevens Creek Quarry.

Lehigh began using city streets after the county discovered the company was creating an illegal haul road to connect its property to Stevens Creek Quarry. The companies have been ordered to stop transporting the crushed rock until the county approves a separate application to legalize the haul road.

Simitian said the company’s responsiveness to complaints has been “a mixed bag,” but the relationship between the county and quarry has much improved in recent years, as well as communication with the patchwork of regional, state and federal agencies that regulate Lehigh.

“I’ve tried to communicate my view with the Quarry and cement plant operators that they’ve got a money machine out there in the hills, and if they want to keep that money machine productive, they need to do a top-flight job of compliance,” Simitian said. “I would like to think that message sunk in.”

A key question, Simitian said, will be how much discretion the county has over the application, given the company’s vested rights.

“This is a significant expansion of the operation and I think … there could be a lot of back and forth before the application is even deemed complete,” Simitian said.

The city of Cupertino plans to hold a community meeting — no date has been set yet — to gather community input and feedback on the company’s proposal, interim City Manager Timm Borden said.

While the city of Cupertino doesn’t have oversight over the quarry, any expansion of mining should take residents into account, Councilman Darcy Paul said.

“People often say the company was there for a much longer time than neighbors, and there’s some point to that,” Paul said. “But in terms of a new pit, I don’t believe that concept applies. … Residents should be an important part of the outreach process for the county.”

Lehigh’s application will require the county to prepare an environmental impact report, and eventually, the county’s planning commission will have to approve it.

Thy Vo covers government in Santa Clara County and the city of Santa Clara for The Mercury News. She's a Southern California native and started her journalism career watchdogging local government in Orange County, California for the nonprofit news website Voice of OC.

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